I did this

I thought the error message was referring to the argument to -d and spent a while scratching my had trying to figure out why the first l of null would be reported as the location of the error. (In this instance it may be obvious, but this is a reduced example of a long command line.)

I expected the following

I suggest that the error message be clarified. For example:

Change "column" to "character"

Include the failing argument in the error message:

curl: (3) [globbing] unmatched brace at character 20 of «http://example.com/{foo»